Light Scattering as a Monitoring Device in the Studies involving Macromolecules

Molecular Biology Unit, Department of Biochemistry, Institute of Medical Sciences, Banaras Hindu, University, Varanasi-221 005

Light scattering has been used as a monitoring device in the study of the macromo­lecules like proteins, nucleic acids and nucleoprotein particles like ribosomes and viruses, using a spectrofluorometer for the purpose. The molecular weight of a globular protein can be determined by measuring the scattering by a 10-20 micromolar solution and com­paring that with the standard proteins of known molecular weights. In case of polyribo­nucleotides the scattering is dependent not only on the chain length but also the higher order structures. Scattering by ribosomes or viruses is proportional to their amounts within certain range. Light scattering measurements also reflect the differences in the structural features of viruses. The decrease in light scattering due to the degradation of the substrate has been utilized for following the action of enzymes like RNase I on polyri­bonucleotides.